A heroin-junkie lawyer who once represented mother-and-son killer grifters Santé and Kenneth Kimes was sentenced to a year in jail yesterday for scheming with his girlfriend to steal nearly $80,000 from 9/11 charities.

Matthew Weissman, 47, had been convicted Nov. 5 of grand larceny.

Prosecutors said he and girlfriend Evelyn Wellens, both of Edgewater, N.J., falsely told charities they suffered financially from the World Trade Center collapse.

Wellens, sentenced last week to two to six years, had falsely claimed she lost her job working for Weissman. He backed her story and claimed he lost business at his Broadway law office and had to let her go.

Manhattan Supreme Court Justice John Bradley called Wellens “the prime culprit,” but told Weissman, “You are a lawyer, and you should have known better.”

Assistant District Attorney Marcy Chelmow condemned Weissman for “dancing on the graves” of the tragedy’s victims.

Wellens pocketed $50,000 from the Federal Emergency Management Agency, $17,000 from the Red Cross and $3,000 from Safe Horizon.

Weissman pocketed $4,000 from Safe Horizon and $4,000 from the Red Cross.